Provinces will try to move sales online, but that won’t be a solution either, predicts John Prentice, president of Ample Organics, which supplies software to the cannabis industry.

“I suspect that there just will not be product to sell, and the (online) store will have sporadic moments of product availability. They’ll acquire 50 kilos of product from a licenced producer, then send you an email, and they’ll sell out in a couple of minutes. Then you’re waiting for the next shipment to come in.”

“I do think the supply issues are going to be that constrained here in the country, especially on Day 1.”

WATCH: The NDP are questioning why edible cannabis is not included in the Liberals’ marijuana legislation and are asking them to fix the issue.

“In the event that somebody applies for a licence, the process can take up to two years before they’re approved by Health Canada to even start cultivation activity,” Prentice says. “Then they need to get the inventory to start cultivation, and the permitting for that can take a little while. Then you have cultivation time on top of that, plus the buildout of the facilities.”

“Starting from nothing, you could be three years before your plants are in the grow room, growing for their first harvest.”

Every U.S. state that has legalized recreational pot has taken between 18 months and a year for supply to start to meet demand, he says.

“Washington was the same, and we’re watching Nevada go through it right now. They had to issue emergency licences to help open more dispensaries and grows.”

Some provinces show awareness of the issue. New Brunswick, which became the second province to announce its plan to sell recreational pot earlier this month, announced that it had signed supply contracts with producers in Moncton and Smiths Falls, Ont., to make sure that there would be at least some marijuana to sell.

WATCH: The New Brunswick government has become the first Atlantic province to reveal its plans for the legalization of marijuana. Adrienne South has more information on the details of the plan.

The problem, apart from disappointed customers and tax revenue left on the table, is that legal — but empty — marijuana stores mean that governments can’t shut down the black market in pot, which was advertised as the main point of legalizing in the first place.

“There’s a real push to get this over the line,” Prentice says. “It was a Trudeau election promise, and something that was very important to his campaign, but at the same time they haven’t really given the opportunity or sufficient time to create the infrastructure deployment of legalization. The timeline is tight, and plants don’t grow overnight.”

WATCH: Police services across the country asked the federal government to put the brakes on legalizing pot, saying they won’t be ready to deal with it by next summer.